St. Paul daily globe. [volume] (Saint Paul, Minn.) 1884-1896, 1887-01-30
HOW TO PAVE STREETS
Capt. Eugene Griffin Assistant Engineer
at Washington, D. O., Talks on This
Important Subject.
Asphalt Pavement Compared With the
Other Varieties as to Cost and
Durability.
Views of an Expert as to the Differ
ent Kinds of Asphalt Now
in Use.
The Kerr Paving in st. Paul--Q ues-
lions of Especial Interest Ably
Discussed.

of Washington city. is in st. Paul, and
has been in consultation with numerous
gentlemen who are especially interested in
public Improvements. Capt. Griffin has
had large experience with asphalt paving,
and is considered an authority on all points
, in connection with the use of this article.
In view of the fact that st. Paul is so deeply
interested in this kind of paving just at
present, Capt. Gritfin's ideas will be Of
value. He is not in any way Interested in
paving. but speaks as an experienced public
officer.
A tirst-class pavement consists essentially
of concrete base covered by a wearing sur
face, he said 10 d GLOBE reporter yesterday.
The base is permanent and gives the requisite
. strength and solidity. The wearing surface,
as its name indicates, is designed to protect
the base and to receive the wear and tear of
street traffic. 1t requires repairs and even
complete renewal at more or less frequent in
tervalS. The wearing surface should be in
expensive, smooth, but not slippery, noise
less, durable, water-tight and easily repaired.
NO pavement has ct been constructed which
fulfilis all of these conditions. TIE granite
block pavement is durable, cheap consider
ing its durability and, when properly laid with
tarred and graveled joints, is water-tight; on
the other hand it is rough, noisy and slippery.
The asphalt pavement is smooth, causes little
noise, is water-tight ard durable. though less
so than granite. Its first cost is less than
granite, but the cost of maintenance is
greater The coal tar dlstiate pavement
has all the advantages Of the asphalt and is
less expensive. 1t is perhaps not SO dur
able, though the difference in this respect is
slight.
The wood pavement-the first-class pave
ment, on concrete foundation, with graveled
joints-is less noisy, less slippery and more
comfortable than any of the foregoing. 1t is,
however less durable and more expensive.
1Ix,kl-
extensively throughout the Northwest,
can only be regarded as a temporary
expedent. Though its first cost is small, its
rapid deterioration makes in the end far more
expensive than any other style Of pavement
yet invented. No form of pavement is suit
able for boulevards and suburban GriVeways
where fast driving is permitted. Nothing is
more injurious 10 fine horse than fast drlv-
ing on the inelaStic pavements OF urban
streets; but the objections frequently urged
against such pavements on this account are
unreasonable. Pavements are not intended
for fast driving; outside of sanitar, condi-
lions they have really but two objects-com-
fort in driving and economy i'll hauling.
Streets subjected to very heavy traffic require
DURABLE PAYMENTS
and unfortunately the qualities of smooth
ness and durability are not generally cock
istent. The smooth concrete is less durable
than the rougher granite. Stone blocks are
therefore generally used on business streets,
less Travelled streets. On such streets as
Broadway N Y, granite blocks are always
laid On q base of ny draulic concrete, but
much variation is found in the size and mode
of laying the blocks. To afford good footing
for the horses the blocks should be narrow,
not over three or four inches wide, and for
sanitary reasons the joints should be thor
oughiy filed with wel-rammed gravel and
paving cenent-coal tar. Very durable, sat
satisfactory and cheaper pavements
are obtained by laying the blocks
on gravel and sand foundation. If the
work is PR perly done such a pavement an
swers equally well for streets not subjected
to the heaviest class of traffic. Asphalt pave
ments are not now regarded with as much
favor as formerly in Europe; i. e. in London
and Paris, and this fact is freQuen tly ad
vanced as an argument against the introduce
ton of such paVements III this country. The
European pavements have invariably been
constructed of the Geyesel or Neuf-
chatcl asphalt, which gives. "a very Slip
perry surface. The Trinidad as
phalt, which is used in this country,
gives much more gritty surface, and the
difference is very marked in wet weather.
Penns lvana avenue, in Washington, is
paved with Neufchatel asphalt from First
avenue to Sixth street east, and this portion
OF the avenue is always dangerous at the be-
ginning OIL a rain. Asphalt pavements are
more slippery when slightly wet than when
thoroughly drenched with wafer. In Paris II
was found necessary 10 sand the asphalt
streets in damp weather. In London the
combination OF dirt with the danpness of the
from which the streets are rarely,
if ever, clear, and this con-
tributes in marked degree to the slipperi-
ness of the pavements In Washington we
have 81 miles. l,j51, 4S0 square yards, of con-
crete paYements, sheet asphalt asphalt blocks
and coal tar distllate. This is far in advance
of any other city in the United States, and
the pavelnents have been laid tor longer pc
riods. With the gritty Trinidad asphalt on
objection on the score OF slipperiness has
ever leen urged. Careful traffic observations
in London, Paris and throughout this country
have established the fact that a horse falls
more frequently on granite than on asphalt,
and less frequently on wood than on either
granite Or asphalt Fully one-third of the
concrete pavements of Washington consist of
the coal tar dlstillate. Considerably more
than half of the new paveTents laid during
the past summer were of this class. 1t con-
sists of bituminous concrete base composed
of parts broken stone cemented with coal
tar. a layer of binder composed OF IA parts
stones mixed hot with paving cement, and
wearing surface composed essentially of paw
ing cement, 25 per cent. asphalt 10 per cent
coal tar distiliate. sand and pulveriZed stone
laid in the same manner as the asphalt pave
ment. There is little difference in the
appearance comfort and durability Of good
asphalt and distilate pavements Some OF
the early dstillate pavements Of Washington,
Wulcn were inpTOp6Tly anu COiupOSGu Oh
poor materials, went to pieces rapidly, but
othels which were properly laid have shown
most satisfactory endurance. street, one
3f the principal residence streets Of Washing
.Ou, was paved with distllate In 1875, eleven
pears ago. 1t is now in excellent condition,
and has not cost the district cent for MAIN
tenance during that period There are many
pavements in Washington of the same age
and composition as the X street pavement
which have shown the same endurance,
Many of the ashhalt pavements of Washing
ton ave worn into waves under constant
r.ffic, and have developed cracks extending
entirely across the street. The latter fault
is due to differences of temperature. and the
former probably 10 undue softness under the
HOT SUMNER SUN
and lack of cohesion between the surface
and the base. Formerly the asphalt SUI face
was applied in layers called respectively The
cushion and wearing COATS but in view of
the above faults the specifications for the
pre. MT year were changed to require the
entire surface TO be applied in one layer, two
and one-half inc hes thick when fully COM
pressed. This Will give more strngth to resist
contraction and will oppose greater resist
ance TO the tendency to creep into waves.
The distiate pavement, though laid in three
coats, coale sees into ore compact mass and is
free from both of the above defects. 1t is
laid with q three inch base, one and one-haf
inch of ''binder,'' and one and one-haif inch
of wearing surface, total thickness six inches.
Each LAYER is thoroughly rolled with heavy
steam roller With both the asphalt and dis
siIlate pavemeuts, the great difficulty has been
20 so egulate the consistency of the surface
material that it shall be neither too soft in
summer nor too hard in winter. If too soft, it is
siisagreeabe for travel, becomes marked and
disfigured by boots and wheels and may even
sose its proper slopes. II too hard in winter
IL becomes brittle and ears rapidly under